The present invention relates to radio frequency (RF) signal measurements, and more particularly to the signal type identification of an unknown signal.
In measuring and testing RF systems there occur from time to time interfering signals. This may show up on a spectral display, such as that generated by a spectrum analyzer, as an extraneous signal in the frequency domain, as shown in FIG. 1. A skilled operator, technician or engineer may manually identify the interfering signal by making appropriate adjustments to the spectrum analyzer control parameters and having skill in identifying those parameters that are unique to different types of signals, both modulated and unmodulated. There are many signal types that may occur in the normal environment, such as IS-95 CDMA signals, North American Digital Cellular (NADC) TDMA signals, Global System for Mobile (GSM) TDMA signals, Analog Mobile Phone System (AMPS) FM signals, Continuous Wave (CW) signals and W-CDMA or CDMA 2000 signals.
In normal field testing and measuring conditions the operator may not be a skilled operator, technician or engineer and, thus, may not have the skill and experience necessary to discriminate and identify to which of the signal categories a particular unknown signal belongs. What is desired is an instrument that automatically identifies an unknown modulated signal with a reasonable confidence level for the unskilled operator.